Annotations for _Roughing It_ (UCal Press, 1993), p. 702 state the
"mendicant Blucher" was identified by Clemens in a letter to Mary
Mason Fairbanks of 29 June 1871 as John Henry Riley.
Annotations for _Mark Twain to Mrs. Fairbanks_ (Huntington Library,
1949) p. 155 indicate that Clemens apparently tried to delete the name
Riley from the letter and substituted Blucher, the name being used in
a lectures Clemens was writing titled "Reminiscences of some
Un-Commonplace Characters I have Chanced to Meet."
The character Blucher/Riley is not to be confused with Blucher from
_Innocents Abroad_, the ingenious youth in _Innocents Abroad_.